Field of the Invention
The present invention relates to a composite profile evaluating method and a composite profile measuring device for a camshaft that opens and closes an engine valve provided in a cylinder of an internal combustion engine, in accordance with a composite profile corresponding to the relative positioning of a pair of a fixed cam and a movable cam.
Description of the Related Art
For example, in Japanese Laid-Open Patent Publication No. 07-190702, there is proposed an inspection method for a camshaft having cams of the same shape and same phase. More specifically, contact elements, which are capable of moving in a direction perpendicular to an axis of the camshaft, are brought into contact with the circumferential surfaces of the aforementioned two cams, and the camshaft is rotated in this state. In accordance therewith, it is determined that the smaller the amount of relative movement of, both contact elements to be detected, the higher the dimensional accuracy and assembly accuracy of the cams becomes.
Incidentally, for example, according to Japanese Laid-Open Patent Publication No. 2002-054410, in order to arbitrarily control the opening angles of engine valves of an internal combustion engine, instead of cams of the same shape and same phase, a camshaft has been proposed which comprises movable cams and fixed cams for which the relative positioning (phase difference) therebetween is variable.
With such a camshaft, since the phases of the fixed cams and the movable cams are not limited to being mutually the same, even if the detection method of Japanese Laid-Open Patent Publication No. 07-190702 were applied thereto, it would be difficult to evaluate the state of the cam surfaces. Consequently, it is indispensable to evaluate the state of respective cam surfaces separately, by bringing contact elements into abutment against each of the fixed cams and the movable cams.